First he struck a deal with the GOP, and now comes the hard part. President Obama and VP Joseph Biden went into campaign mode Tuesday, attempting to rally Congressional Democrats to support their new tax-cut plan. Biden, a senator for 36 years, has been meeting with his former colleagues, selling the pact as “a good deal” and plans to address the House Democratic caucus tomorrow. Obama, who negotiated the deal with Senate Republican leader Mitch McConnell, needs 18 Democratic senators to support the plan in order to prevent a filibuster—and that’s assuming that all Republicans vote for the plan. About a dozen Democrats have already voiced concerns; Bernie Sanders, an independent senator, has already threatened a filibuster.